Monday

Mar 5, 2018 at 3:15 PMMar 29, 2018 at 3:20 PM

SpeakEasy Stage Company’s production of “Every Brilliant Thing” relies on an outstanding performance from a supporting actor: You.

Written by British playwright Duncan Macmillan, the play tackles the subject of mental illness by introducing us to the narrator, who, as a child, tried to nurse her mother through depression by making a list of all the little reasons that life is worth living: ice cream, water fights, staying up past your bedtime.

As an adult, she gains a deeper understanding of how important the list is in her own life. And all along the way, the audience plays key, improvised, supporting roles in the telling of the story.

Patrons are such an important part of “Every Brilliant Thing” that Adrianne Krstansky, who plays the featured role in this Boston premiere of the play, has worked with an audience since the third day of rehearsal. And she’s been amazed by their contributions.

“People do beautiful, astonishing things,” says the actress, who performs the show through March 31 at the Boston Center for the Arts. “There are moments when (audience members) have taken the reins and added to the story in ways that are so honest and true. They allow parts of themselves to come through. It almost feels like a great jazz ensemble. We are truly telling the story together.”

In a theater world hungry for unique stage experiences, “Every Brilliant Thing” seems to be providing one. In past productions, theater critics have been awed by the audience participation. Playing a veterinarian, a counselor or a kid, their simple, unaffected performances have built some of the play’s most poignant scenes.

The onstage director-choreographer-ringmaster of it all is Krstansky. Her job begins even as the patrons enter the theater, as she greets audience members and tries to determine who’s ready for their close-up.

Crafting these unrehearsed moments live onstage requires enormous skill as an improviser.

“I’ve really learned to surrender to the moment,” says Krstansky, who recently moved from Newtonville to Watertown with her family. “Whatever happens is great. There are no expectations. There’s great freedom in realizing that. Self-acceptance is one of the themes of the play, so it’s a celebration of the small and beautiful things that take place in the theater.”

Performing the role has also made Krstansky a better actress, honing some of the most important and elemental skills for an actor.

“It reminds me to embrace spontaneity,” says the actress. “It reminds me of the importance of listening and trusting the other person onstage with you.”

But is it hard to trust a fellow actor who perhaps has never before set foot on a stage?

“I realize that someone may get tongue-tied, but even that is great,” she says. “It is what it is. I’m really not worried about the audience (performances) at all.”

Fine, but the audience may be worried about her. Maybe it was Krstansky’s dream to be an actress, but for many theater patrons, the idea of getting up onstage is the definition of a nightmare. Add in the fact that they don’t know their lines (because they don’t have any lines) and you may have a premise that keeps audiences away in droves.

Have no fear, says the actress.

The cameos are brief, and it’s part of Krstansky’s job to determine who will be – or won’t be – comfortable enough onstage. And anyone who strongly objects can probably let Krstansky know when entering the theater.

“If people have fears about the audience involvement, I think those fears will be quickly allayed,” she says. “It’s a very gentle and supportive environment.”

It probably comes with the territory. “Every Brilliant Thing” broaches the subject of depression, an issue that’s slowly emerging from the dark into the light.

“I’ve had experience with this in my own life,” says Krstansky. “There are very few people whose life has not been touched by depression in some way. We must remove the stigma and give people permission to name it and talk about it in a way that feels connected and supported.”

“Every Brilliant Thing” has become part of that dialog.

Krstansky expects some patrons will have a personal connection to depression. She’s seen it already.

“I can see people in the audience nod when I say something,” says the actress, “and I’ve even heard people say, ‘Yes.’ Many moments in the play ring true for people who are familiar with the issue.”

If Krstansky has a particular empathy with the supporting actors who will pop up in her show, perhaps that’s because she’s been one. She’s landed small roles in some of the big-budget movies that occasionally come to town.

As a result of one of those experiences, she should be forgiven if she has a biased opinion in the Leading Actress category at the Academy Awards ceremony.

She’s a fan of Frances McDormand (“Three Billboards Outside Ebbing, Missouri”), as a result of the time she spent with the star on the set of HBO’s “Olive Kitteridge.”

Krstansky’s review of McDormand as a person is as superlative as her review of McDormand the actress.

“She’s a huge star, and yet she took the time to run lines with me,” says Krstansky. “She knows you’re nervous in a situation like that, and yet she took me in and made me feel comfortable. We ended up talking about our kids. She taught me so much about professionalism and generosity. It was extraordinary.”

“Every Brilliant Thing” runs through March 31 at the Boston Center for the Arts. Tickets start at $25. Call 617-933-8600, or visit speakeasystage.com.